Process for the production of ammonium



United States Patent 3,123,438 PROCESS FOR THE PRODUCTION OF AMMONIUM BERYLLIUM COMPOUNDS Wallace W. Beaver, South Euclid, and Byron B. Lympany, Willowick, Ohio, assignors to The Brush Beryllium Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Filed June 9, 1960, Ser. No. 34,888

4 Claims. (Cl. 23-88) This process relates to the selective fluorination of the metal content of beryllium-containing ores and more particularly to the selective fluorination of such metal content with ammonium double fluoride salts.

A principal object of the invention is to provide a process for selectively extracting from beryllium-containing ores the beryllium content in the form of beryllium-containing compounds which can be converted readily into beryllium metal, and particularly in the form of ammonium berryllium fluoride.

A correlative object is to produce from the berylliumcontaining ore a reaction mass in which the silicon in the ore is substantially unreacted so that the resultant beryllium compounds and other metal compounds are substan tially free from silicon and may be separated readily from the reaction mass.

A more specific object of the invention is to provide a process for the selective fluorination and extraction of the beryllium and other metal content of beryllium-containing ores, which process is effective not only for the higher grade beryllium-containing ores but also for the lower grade beryllium-containing ores, even those having a beryllium content of less than 1% by Weight.

Another object is to provide a process for the selective fluorination and extraction of the beryllium content from such ores whereby substantially the entire beryllium metal content is recovered.

Other objects and advantages will become apparent from the following description wherein a preferred embodiment of the process is disclosed for purposes of illusstration.

Beryllium is found in many ores, but beryl ore is the chief source for the commercial production of beryllium metal, as it is practically the only commercially available ore in which beryllium is found in quantity. Accordingly, for purposes of illustration, the process is described as applied to beryl ore, its application to other berylliumcontaining ores being apparent from the illustrative example.

Throughout the following specification reference is made to beryllium-containing ore. This term is used herein to describe an ore in which the beryllium content is in the form of one or more beryllium compounds. The term high grade beryl or beryllium-containing ore is used to identify beryl or beryllium-containing ores in which the beryllium oxide content is at least and generally from 10 to 14%, by weight, of the ore. The term low grade beryl or beryllium-containing ore is used to indicate such an ore in which the beryllium oxide content is less than 10%, and as low as /2 to 1%, by weight, of the ore. correspondingly, the term high beryllium yield is used to define a yield of from about 92% to about 100% by weight of the beryllium content of the particular ore.

Beryl ore is very resistant to chemical attack by acids other than hydrofluoric acid, but this reagent is not very practical for extraction purposes, as it attacks all the components of the ore, including the silica which is always present in major proportions. Further, hydrofluoric acid is difiicult to handle in processing because of its corrosive and toxic properties. It is known that beryl ore can be made reactive by altering its physical properties, and one commercial process is based on this characteristic. In this commercial process, the crystalline structure of the 3,123,438 Patented Mar. 3, 1964 ice beryl ore is first changed by fusing the ore at temperatures in excess of 1600 C., and quenching the melt to a frit. Next, the frit is heat treated and then reacted with strong sulfuric acid at temperatures sufliciently high to form insoluble silico compounds, such as silicic acid, and soluble beryllium and aluminum sulfates. The beryllium sulfate is subsequently converted to ammonium beryllium fluoride crystals, which are decomposed to provide beryllium fluoride.

The practice of this process provides a final yield of about of the beryllium content of the ore, but, because of the reaction of the silica and acid, requires quantities of sulfuric acid disproportionate to the small amount of the acid necessary to produce the beryllium and aluminum sulphates.

In another well known commercial process, alkali metal double fluoride salts, such as sodium ferric fluoride or sodium silicofluoride, are reacted with beryl ore to produce an initial sodium beryllium fluoride product. As the sodium beryllium fluoride product cannot be thermally decomposed directly, it must be converted to ammonium beryllium fluoride for thermal decomposition to provide beryllium fluoride.

In accordance with the present invention, ammonium beryllium fluoride can be produced directly, by reaction of the beryllium-containing ore with various inorganic ammonium double fluoride salts. The reaction must be carried out at predetermined temperature and pressure conditions in a closed system. Ammonium silicofluoride, ammonium bifluoride, and ammonium ferric fluoride, are effective in the practice of the invention. Ammonium silicofluoride is especially preferred became of its low cost, ease of handling, and commercial availability.

Broadly, the invention comprises reacting inorganic ammonium double fluoride salt with high or low grade beryllium-containing ore at relatively low to moderately high pressure, and at a temperature ranging from about 200 C. up to that which can be tolerated by the reactor without rupture or serious damage and without chemical reaction between the reactor and the charge at the partic ular pressure employed, for a time period sufficient to substantially complete the reaction of all of the salt with the beryllium content so that the major portion of the reaction product resulting from the reaction of that quantity of ore which reacts with the salt is a complex salt of ammonium fluoride and beryllium fluoride, the formula NH F-BeF being one example. With the preferred stoichiometry and ammonium silicofluoride as the inorganic ammonium double fluoride salt, the resultant complex salt is mono-ammonium beryllium fluoride.

Preferably, the amount of salt employed is just sufiicient to cause substantially all of the beryllium content to react therewith, and preferably the upper limit of the temperature is about 750 C.

In a more limited aspect, the invention comprises reacting an inorganic ammonium double fluoride salt selected from the class consisting of ammonium silicofluoride, ammonium bifluoride, and ammonium ferric fluoride, with high or low grade beryl ore, of about mesh or finer. The quantity of the salt is preferably that required to cause the entire metal content of the ore to react therewith. The reaction is effected at a pressure of not less than about p.s.i.g., and at a temperature ranging from about 300 C. up to that which can be tolerated by the reactor without rupture or serious damage and without chemical reaction between the reactor and the charge at the particular pressure employed, until the reaction is substantially comvplete.

In a still more limited and preferred practice of the invention, high or low grade beryl ore, of 100 mesh or finer, is reacted with ammonium silicofluoride in a weight ratio of ore to fluoride salt of about 1.0 to about 0.85, at

a pressure range of at least about "200 p.s.i.g. to about 700 p.s.i.g., and Within a temperature range of about 300 C. to about 550 C., until the reaction is substantially complete and the reaction mass contains a complex salt of ammonium fluoride and beryllium fluoride, incorporating tain 94.45% of the beryllium content of the input beryl ore.

The procedure of Example 1 was followed in conducting the reactions presented below in Table I, with variations of reactants and reaction conditions indicated there- D at least 90%, by weight, of the beryllium content of the in. The process employed in carrying out the reactions of input ore. Table l was tmodified only in Examples 4 and 12, and Initial investigations were carried out using a mild steel only in that the reaction mixtures were introduced into a tube provided with welded end caps. The pressure could reactor vessel in which the pressure and temperature of not be controlled in the completely enclosed mild steel the reaction could be controlled. tubes, but calculations indicated that high yields of beryl- The pertinent data obtained from extensive investigalium metal content were obtained at exceedingly high tion of the beryl ore reaction specifically with ammonium pressures. The apparatus was subsequently refined to prosilicolluoride as the preferred reactant, are presented in vide a reactor vessel in which the pressure could be read Table H below. from a Pressure gauge, and ccmroned as deslfeds TIE This specific process was carried out by intimately mixsubstantial extraction of beryllium content at very high i b l 0% ith h ammgnium silicQifl-uoridg i a Pressuffis was Confirmed y 11063351118 tests conducted weight ratio of ore to fluoride salt noted in the examples in the feacior vessel- F of Table II, and placing the mixtures in a reactor vessel Th.fo11:mng Whlch mcorporae l i f in which the pressure and temperature could be conemblfdlmem of mventlfilm *5 Presenteg as r if trolled. The pressure and temperature conditions, and

. a 1 c g e Rmcessi an to e constru" as a Ions reaction time, are shown in Table 11. The reaction prodrrr t m any respec T) uots were leached with a water solution, and the result- EXAMl LE 1 ing solutions obtained from the leaching were analyzed Eighteen grams beryl ore, of 100 mesh or finer, and for beryllium content, with the results noted.

Table l OroBeO Yield of Example Weight Content Ore Weight of Fluoride React- Ore to Tcmpcr- Pressure Time Be Number of Beryl (Wt. por- Mesh Fluoride, ant Fluoride ature (p.s.i.g.) (hr.) Metal Ore, gm. cent) Size gm. Ratio 0.) (Wt.

percent) 18.0 11.2 100 18.0 (NI'IQQSi Q 1:1 450 6 94.45 23.0 0.68 100 15.35 (Nnmsirfin 10:0. 668 500 3 92.8 10.0 11.2 100 15.36 (NI'I4)3FGF6. 10:1. 536 400 3 96.6 204.0 12.6 200 246.0 (NHQaFeF 101.2 400 9801,260 3 97.22 15. 0 11. 2 100 15. 0 (NH FeFo 1:1 500 3 97.0 13.2 11.8 -100 12.0 (NHQsFGFs. .91 600 3 100 10. 66 11.2 100 12.81 (NHmFQF .0 .768 590 6 98.0 11.77 11.2 100 17.65 NHJl 1. 11.5 300 6 96.2 11.77 11.2 100 17.65 NI-nHF 1. 11.5 400 6 99.5 14.28 11.2 100 16.0 NEnHF z .12 500 3 95.6 19. 5 12.0 200 19.5 Nrnnr 1 =1 400 3 97.0 225. 0 12.6 200 225. 0 NH HF 1:1 400 700-1, 630 4% 99. 14 20. 5 12. 0 200 18. 5 NI-LHFZ :0. 9 400 3 95. 0

1 Closed system welded tube reactor.

Table 11 Weight OreBeO Weight of Yield 01' Exof Beryl Content Ore (NHQgSiF Ore to Temper- Pressure Time 136 Metal ample Ore, (wt. Mesh Reactant, Fluoride aturc (p.s.i.g.) (hr.) (wt.

gm. percent) 8129 gm. Ratio 0.) percent) 1 Closed system welded tube reactor.

From the data presented in the above examples, it will be observed that the process is capable of providing high yields of the beryllium content of the input beryl ore by reaction of said ore with inorganic ammonium double fluoride salts under various pressure and temperature conditions. The high yields of beryllium metal content obtainable with the process from low grade beryllium-containing ores are particularly shown in Examples 23 through 28. The process can be carried out by reacting equal propontions, by weight, of the inorganic ammonium from the leaching step was analyzed and found to condouble fluoride salts w-tih the ore, although higher or lower proportions may be used, dependent on the temperature and pressure conditions of reaction. For economy and ease of operation, the preferred pressure and proportion by Weight of the reactant salt are the lowest capable of providing high yields of extracted beryllium.

Any type of reactor may be employed in the practice of the process provided it is capable of withstanding the pressures used, and of permitting the predetermined temperatures and pressures to be controlled therein. Although the use of ammonium silicofluoride, ammonium (ferric fluoride, .and ammonium bifluoride as inorganic ammonium double fluoride salts are shown in the above examples, it is also possible, although in some respects not as desirable, to use other inorganic ammonium double fluoride salts, such as ammonium fluo borate, and ammonium hexofiuophosphate.

Generally, high grade beryl ores containing from ten percent to about fourteen percent, by weight, of beryllium oxide are used in the commercial practice of the process, but as noted in the above examples, the process is capable of providing high yields of the beryllium metal content of low grade ores which contain less than ten percent, and even less than one percent, by weight, of beryllium oxide.

An important feature of our invention is the employment of proper and controlled pressure during a reaction with beryllium-containing ore of inorganic ammonium double fluoride salt selective to the metal components of the ore which in beryl ore are beryllium and aluminum, in such manner that high yields of the beryllium content can be obtained by subsequent leaching of the reaction mass.

The primary and unexpected advantage of the invention is that it effects the reaction of the ammonium salt with the metal components of the beryllium-containing ore which in beryl ore are beryllium and aluminum, while the silica, about 70% by weight of commercially available beryllium-containing ore, remains substantially unreacted, whereas it would be expected that all the constituents of the ore, including the silica, would be fluorinated.

Thus the silica would be expected to be fluorinated to form silicon tetrafluoride gas, in the absence of sodium or potassium capable of forming insoluble silicates with the silicon. However, in the present process, the waterinsoluble silicon-containing compounds, other than fluosilicates, remain as a sludge when the reaction product is leached with water to remove total soluble material from the reaction mass. Silicon tetrafluoride is not detected in the analysis of gases formed during reaction. The absence of both silicon tetrafluoride gas in substantial amounts, and of salts containing silicon and fluorine, substantiates a highly selective reaction of the ammonium double fluoride salts with the metal components of the ore, when the prescribed conditions of the process are followed.

For example, gases evolved at 400 C. during two individual reactions of high grade beryl ore and ammonium silicofluoride, in an ore to fluoride ratio of from 1.0 to 0.9, at 1240 and 1330 p.s.i.g., respectively, were found by analysis to contain about 77% and 85%, respectively, of ammonia, by volume, the balance being mainly hydrogen and nitrogen.

Analyses of many solutions obtained by using suflicient water to leach only the much more soluble material from the reaction mass which is obtained by reacting ammonium silicofluoride and beryl ore have shown said material to be mono-ammonium beryllium fluoride.

It is thus indicated that the main product of the foregoing reaction with the beryllium content is generally mono-ammonium beryllium fluoride which is represented herein by the formula NH BeF and sometimes by its alternative complex NH F-BeF The balance of the input of the ammonium fluoride from the ammonium silicofluoride reacted with the alumid num to convert the aluminum content of the ore to a relatively insoluble mono-ammonium aluminum fluoride, NH AIF On the basis of the above observations, the following predominant reaction takes place:

To a limited extent, there is a side reaction, as follows:

This side reaction seems to account for not more than 8% of the total yield of beryllium, and usually is not more than 2 to 3 thereof.

It is believed that any tendency toward a reaction of the inorganic ammonium double fluoride salt with the silicon content of the ore tending to produce silicofluoride is suppressed by the following known reaction: 2NH +SiF 2NH SiF The product, silicon tetrafluoride diamminate, is a white sublimable solid similar to ammonium silicofluoride.

It will be readily observed that the process has the advantage of providing a complex salt of ammonium fluoride and beryllium fluoride directly from beryllium-contain- F ing ores, and which complex salt can be readily converted to normal ammonium beryllium fluoride, represented herein by (NH BeF by the addition of ammonium fluoride. Prior processes are characterized by the complexity of the treatments of several intermediate compounds to obtain the normal ammonium beryllium fluoride required for subsequent reduction to the metal. The required stoichiometry is a still further advantage of the invention, as the required low ratio of ore to ammonium double fluoride salts affords a saving in the amount of the reactant salt. The use of low-priced ammonium silicofluoride, the preferred reactant, in a low ore to salt ratio of about 1.0 to 0.85 is particularly indicative of the economic advantages of the invention. The process has a further distinctive advantage over prior processes, in that when the preferred process conditions are maintained, high yields of from about 95% to about by weight of the beryllium content of the ore may be extracted and recovered.

It will be readily apparent that modifications in the practice of the process are possible, and the invention is not to be limited only to the specific examples disclosed.

Having thus described our invention, we claim:

1. In a process for selectively fluorinating substantially completely the beryllium content of beryllium containing ores, the steps comprising intimately mixing finely divided beryllium containing ores with a quantity of ammonium silicofluoride at least suflicient for the reaction of substantially the entire beryllium content of the ore therewith, reacting the mixture at a minimum pressure of from about 200 p.s.i.g. to about 1700 p.s.i.g. and at a temperature ranging from about 200 C. upwardly to about 750 C. so that substantially the entire amount of the beryllium can occur for a time suflicient to effect reaction of the ammonium silicofluoride with substantially the entire beryllium content of the ore, so that substantially all of the beryllium contained in the reaction product is a complex salt of mono-ammonium beryllium fluoride, the formula for which is NH F-BeF 2. The process according to claim 1 wherein the ore is 200 mesh or finer, and the maximum temperature is about 700 C.

3. The process for selectively fluorinating substantially completely the beryllium content of beryllium containing ore, comprising intimately mixing the beryl ore of a particle size of 200 mesh or finer with ammonium silicofluoride,, an ore to fluoride salt ratio of from 10:05 to 1.0:l.2, reacting the mixture at a minimum pressure of from about 200 p.s.i.g. to about 700 p.s.i.g. at a temperature ranging from about 300 C. to about 600 C. until the reaction is substantially complete and thereby substautially all of the beryllium contained in the reaction product is mono-ammonium beryllium fluoride, the formula for which is NH BeF 4. In a process for selectively fiuorinating substantially completely the beryllium content of beryllium containing ores, the steps comprising intimately mixing finely divided beryllium containing ore with a quantity of ammonium silicofluoride at least sufficient for the reaction of substantially the entire beryllium content of the ore therewith, reacting the mixture at a pressure of from about 200 p.s.i.g. to about 1700 p.s.i.g. and at a temperature ranging from about 200 C. upwardly to about 750 C. so that substantially the entire amount of the beryllium can occur for a time suificient to effect reaction of the ammonium silicofluoride with substantially the entire beryllium content of the ore, so that the reaction product is the complex salt of ammonium fluoride and beryllium fluoride, the formula for which is NH F-BeF which 8 complex salt is one which can be readily converted into normal ammonium beryllium fluoride, the formula for which is (Nl-I BeF by the addition of ammonium fluoride.

References Cited in the file of this patent UNITED STATES PATENTS 2,081,984 Claflin June 1, 1937 2,162,323 Wille et al June 13, 1939 10 2,196,043 Adamoli Apr. 2, 1940 2,399,178 Furlaud Apr. 30, 1946 2,532,102 Kawecki et a1 Nov. 28, 1950 OTHER REFERENCES 5 Mellor: Comprehensive Treatise on Inorganic and Theoretical Chemistry, vol. 4, pages 229230 (1923). Longmans, Green and Co., New York.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3 128 438 March 3 1964 Wallace We Beaver e1; ale

n the above numbered petthat error appears i t should read as It is hereb; certified ent requiring correction and that the said Letters Paten corrected below.

Column 6, line ll for "90%" read .--99%--; line 69 strike out "the".,

Signed and sealed this 7th day of July 1964,

(SEAL) Attest:

EDWARD J. BRENNER ERNEST w. SWIDER Attesting Officer Commissioner of Patents 

1. IN A PROCESS FOR SELECTIVELY FLUORINATING SUBSTANTIALLY COMPLETELY THE BERYLLIUM CONTENT OF BERYLLIUM CONTAINING ORES, THE STEPS COMPRISING INTIMATELY MIXING FINELY DIVIDED BERYLLIUM CONTAINING ORES WITH A QUANTITY OF AMMONIUM SILICOFLUORIDE AT LEAST SUFFICIENT FOR THE REACTION OF SUBSTANTIALLY THE ENTIRE BERYLLIUM CONTENT OF THE ORE THEREWITH, REACTING THE MIXTURE AT A MINIMUM PRESSURE OF FROM ABOUT 200 P.S.I.G. TO ABOUT 1700 P.S.I.G. AND AT A TEMPERATURE RANGING FROM ABOUT 200*C. UPWARDLY TO ABOUT 750*C. SO THAT SUBSTANTIALLY THE ENTIRE AMOUNT OF THE BERYLLIUM CAN OCCUR FOR A TIME SUFFICIENT TO EFFECT REACTION OF THE AMMONIUM SILICOFLUORIDE WITH SUBSTANTIALLY THE ENTIRE BERYLLIUM CONTENT OF THE ORE, SO THAT SUBSTANTIALLY ALL OF THE BERYLLIUM CONTAINED IN THE REACTION PRODUCT IS A COMPLEX SALT OF MONO-AMMONIUM BERYLLIUM FLUORIDE, THE FORMULA FOR WHICH IS NH4F$BEF2. 